A light emitting device, e.g., a light emitting diode (LED) is a kind of semiconductor device that converts electrical energy into light. The light emitting device has come into the spotlight as a next-generation light source that substitutes for the existing fluorescent lamps and incandescent lamps.
The LED generates light using a semiconductor device. Thus, the LED consumes very low power as compared with the incandescent lamp that generates light by heating tungsten or the fluorescent lamp that generates light by allowing ultraviolet light generated through high-voltage discharge to collide with a fluorescent substance.
Also, the LED generates light using a potential gap of the semiconductor device. Thus, the LED has a long lifespan, a fast response speed, and an eco-friendly property, as compared with the existing light sources.
Accordingly, a lot of research for replacing the existing light sources with LEDs has been conducted. The LEDs have been increasingly used as light sources of lighting devices such as various lamps, display devices, electronic display boards, and streetlamps.